Evaluation of nano silica on properties and thermal stability of resole resin

In this paper the thermal stability and properties of resole type phenolic resin is investigated. Thermoset phenolic resins have good physical and mechanical properties up to 250 ˚C temperature; however, for high temperature applications modification of thermal stability of resin is very important. Nano silica (SiO2) effect as a filler on thermal stability of the resin is investigated. Thermal properties was studied by means of thermo gravimetric analysis (TGA) to evaluate char yield and differential scanning calorimetric (DSC) to evaluate the resin curing behavior and SiO2 effects on curing reaction heat. Results showed increase of char yield and curing reaction heat in the presence of SiO2. Fourier transform infrared spectroscopy (FTIR) was used to investigate the variation of absorption bands in the presence of SiO2. The results indicated that with an increase of temperature from 200 ˚C to 800 ˚C resin structure was decomposed and volatile compounds including CH4, CO, CO2 and H2O were released out and the resin was carbonized and converted into amorphous carbon. Finally, the microstructure evolution of modified resin and distribution of nano silica in resin matrix were investigated using scanning electron microscopy (SEM). Results showed that silica particles are completely and uniformly distributed in the resin.